This invention relates to a nose cone construction for the gear case of a marine drive.
Marine drives normally include an outboard positioned drive unit which includes a lower gear case formed at its lower end in a manner to provide a generally horizontal torpedo housing. In some instances, water intake openings are provided in the upper portion of the gear case above the propeller drive shaft housing. In other instances, as shown for example in U.S. Pat. Nos. 2,656,812 and 3,487,803, the bore of the propeller shaft housing is closed at its forward end by a conical nose member which includes a plurality of water inlet openings on its periphery. In U.S. Pat. No. 3,487,803 for example, a conical nose head has a bolt which extends into the propeller shaft bore and which is suitably secured at its inner end to a seal support member. The construction is such that the elements are all disposed on a common axis.
In some instances it may be desirable to offset the axis or centerline of the torpedo housing from the axis of the propeller shaft itself. In so doing, the securing bolt also needs to be offset from the centerline of the torpedo. In addition, it is desirable to dispose the water inlet in the most advantageous position.
It is an object of the invention to provide the desired offset, and to improve the positioning of the water inlet, all with a minimum of drag. It is a further object to accomplish the desired results with a maximum of torque retention of the parts involved.
In accordance with the various aspects of the invention, a marine drive unit includes a lower propeller torpedo housing of generally cylindrical configuration having a longitudinal centerline. A propeller shaft is mounted in the housing for rotation on an axis offset from the centerline. The shaft is journalled in a forward bearing assembly which is held in place by a support adjustably mounted to the housing and on the offset axis. A nose is removably secured to the forward housing end by a mounting bolt which extends into the support on the offset axis. A single multi-purpose opening or port in the forward end of the nose communicates to an interior entry passage in the nose. The entry passage in turn merges into a pair of passage branches. One branch is disposed on the offset propeller shaft axis and receives the mounting bolt. The other branch is positioned to communicate with the cooling water passages in the lower unit, and which lead to the marine drive engine. A torque retention and sealing member is disposed between the support and the nose. Furthermore, a torque retention and sealing member is disposed between the bolt head and the inner end of its passage branch.